Mass Effect Harry Potter Crossover
by Dumbnoobe
Summary: The Alliance finds out about the magical world as a result of the first contact war. Shepard is an earthborn witch. Rated M for some instances of strong language, graphic violence, death and gore.
1. Chapter 1

**AN: This is an idea I've had for a while now. I'm putting it up for adoption because between work, study, and writers block i just don't have time to do it justice.  
To anyone who is interested ****in taking on this idea, all I ask is that you PM me with the name the story; and that you mention ****where you got the idea in the  
first ****AN.** **One last thing, the chapter after ****one is a time line starting in 2077 with Liara's birth, and ending in 2183 with the events of ME.  
In between are some AU events that come as a result of the ME/HP crossover.  
**

**NEW AN: After reading a review, I've decided to take the timeline down. In hindsight, I realize that the only thing in it that a observant reader couldn't have guessed; was a spoiler. In better news, also due to this review I've changed my mind about abandoning this story. Anyone who was intending to take up this story, are still welcome to do so. But I think I'm going to take a crack at again.**

Illyria, Plant Elysium, Vetus System, Petra Nebula.  
June-5-2176  
10:00 PM local time.

Gunnery Chief Andrea Shepard stumbled out of a bar, supporting her friends and squad mates. It was a little earlier than they normally left during shore leave. But her idiotic friends insisted that they drink Firewhiskey, Andrea had been drinking it since she was seventeen, and as a result had a certain tolerance to it. Her squad mates on the other hand, did not. This was why, so early in the night, she was the only one in her group that was even somewhat lucid.

Andrea had a thin frame, and an athletic build. She wasn't particularly tall, standing at a hundred and seventy-two centimeters. Her skin was pale, and had the appearance of porcelain. Her unblemished face was heart shaped, and had high cheekbones and a pert nose. Her eyes were a green so light, that they almost looked gray and had a gold ring around the pupils. Her hair was wavy, and came down just passed her shoulders. It was light brown, with blond highlights, and red lowlights.

She knew that most humans, indeed even most asari; would think her pretty, if not beautiful. Andrea didn't care, and rarely wore makeup or jewelry. Unlike her fellow Alliance marines, who were all wearing the regulation off duty uniform; Andrea was wearing the uniform robes of a battle sorceress. The open, hooded robes were in the Alliance colors, dark blue, trimmed in gold.

Corporal Richard Grant, whom she was trying to keep from falling over said. "Anndreeea, why don't we ditch theshes losers; and find a roomm some, hic where. I promise I'll rock your, hic, world." Andrea just laughed at this. Had he been anyone else, she would have been offended; and more than likely would have reported him. Corporal Grant, however, even when drunk off his arse, was still harmless. So once she was done laughing at it, she replied.

"Sorry little Dick, but you know I don't swing that way." Corporal Grant sighed, and grumbled. "Can't blame a, hic, guy for trying." A few minutes later the wizards wireless, which the muggles still called radios; beeped in Andrea's ear, telling her that there was an incoming call. "This is Commander Sanchez, of the SSV Agincourt; whoevers hearing this report in." Andrea touched her hand to her ear to respond, and said. "This is Gunnery Chief Andrea Shepard, reporting in, Sir."

She heard back a few seconds later. "Gunny, are you sober?" Andrea tried to clear her head, and said. "More than the rest of my squad is, sir." She heard a sigh in her ear, and then the commander said. "A few moments ago, a massive fleet of what looks to be pirates and batarian slavers dropped out of FTL in the system, and are now forming up to attack us." The Commander paused for a moment to let what he had said sink in.

"There are too many of them for us to stop all their landing parties, so you and your squad need to ready the colony for a ground assault, as best as you're able." Andrea felt a chill go down her spine, at the thought of what was about to happen. But she remembered her training, calmed her breathing, and responded. "Aye, aye Commander." Andrea then looked at her squad, and tried to think of a way to sober them up quickly.

Not able to think of a better idea, she pulled out her wand from her wrist holster. Her wand was ten inches long, and was made of blackthorn and dragon heartstring. Andrea pointed her wand at Corporal Grant's head and said. "Aguamenti." A jet of cold water shot from her wand, and hit the Corporal square in the face.

He sputtered for a moment, and then looked at her in disbelief. Andrea ignored the look she was getting from the Corporal, and proceeded to do the same to all her other squad mates. Once done, she said in a brisk and commanding tone. "Alright, you heard the commander. We need to find a police station, and get them to help us organize the civilians into a militia." Andrea turned to look at Private Yamato, and said.

"Shifty, get on your OmniTool and find me the nearest station. Hawkeye, find the tallest building you can, and get to its roof. Run over watch for us, and let me know if you see any drop ships, whether they look like bandits or not. Shifty, you got that station yet?" The Private looked up from her OmniTool and nodded sharply, saying.

"Yes ma'am. There's one six blocks to the south." Andrea nodded to the young Private, and said. "Alright then, everybody move out." Ten of them followed Andrea south, while Corporal Richard 'Hawkeye' Grant went north-west to the tallest building in the city. Six minutes later, they entered the police station. As soon as they opened the door, they were hit with a cacophony of sound.

The room before them was a picture of chaos; it looked like most of the people in the room had no idea what they should do. A moment later someone walked up to them and asked. "Are you the marines I was told to expect?" Andrea stepped forward and said. "We are. Gunnery Chief Shepard." She then extended her hand. The man shook her proffered hand, and replied. "Commissioner Collins. I assume you know what's going on." Andrea shrugged, and answered.

"More or less. What's the situation here? How many officers do you have?" Collins sighed, and said. "Of those that are fit to fight. Ten, I'd say." She looked at him in disbelief and asked. "So few?" Collins frowned, and said. "Our job is mostly investigations. The patrols are done by security mechs. " _'Finally, some good news.'_ Andrea thought to herself, and then asked. "How many of those do you have?" "A little under a hundred."

"Alright then. Commissioner, I need a Three-dimensional map of the city, and the surrounding area." Andrea said in a brisk tone. "Right this way ma'am." Collins said, and led them to what looked like a conference room with a map table in the front. Once they were standing in front of the table, Andrea asked. "Does the city have an integrated air defense network, Commissioner?" Collins grimaced at her question, and answered.

"Yes, we do. But unfortunately, it's only a medium range system, and it can't target anything under the city's wall." Andrea called upon her tactical training, and said. "Then they'll have to land outside of its coverage, and approach the city on foot. They can't land to the north or west, because the higher ground would allow us to target them with the city's AA turrets. And they can't land to the east, because there's no cover. If they were to come in from that way, we could pick them off at range."

"So that means that they can only land to the south, on the other side of the forest." Collins said, with a small bit of hope in his voice. "Either that, or in a clearing. Either way though, we know where their point of entry is going to be." Andrea said, pointing to the city's southernmost gatehouse on the map. She then asked.

"What's the state of the city's armory? What types of weapons do you have, and how many of each? How many thermal clips do you have? And finally, how many civilians of fighting age would you estimate are armed already?" Collins was silent for a moment after her questions, but then he answered.

"To answer your last question, I would guess that there are maybe thirty, or so people in the city who have any weapons that would be of use. Most of them are hunters, but a few are ex Alliance. That's not counting the people who have handguns, but I'd rather that they stay in a fallback position, to protect the unarmed civilians." At this Collins look up at Andrea, to see what she thought of it; and at her nod of agreement he continued.

"As for our own weapon stores, it could be worse. We have twenty battle rifles, and SMG's, along with ten shotguns and pistols. Finally, we have one long range sniper rifle, and one medium range sniper rifle. And what was your second question?"  
At her hard look Collins said. "Right, thermal clips. I believe we have twenty-thousand." As soon as he stopped talking Andrea turned to one of her men and said.

"Private Kramer, go grab that Long range rifle, a spotter scope, and as many boxes of thermal clips as you can carry; and get to Corporal Grant ASAP. Once there, the two of you are to set up to target all paths leading to the southern gatehouse.  
Prioritize anyone who looks to be carrying heavy weapons or explosives." "Aye, aye ma'am." Responded the Private. Andrea then said.

"Collins, get on whatever emergency alert system you have, and let the civilians know that they need to go to the most secure building you have near the center of the city. Send one of your men to organize them, and keep them calm. Also, send out a call for all persons between the ages of seventeen and forty-five, who have combat or hunting rifles; to report to the southern gatehouse as soon as they are able." At his nod of acknowledgement, she turned to the others in the room, and said.

"Everyone else, head down to the armory, and load every weapon and box of ammo in to whatever vehicles the station has. Once that's done, head to the gatehouse immediately." To this she received a chorus of, "Aye, aye ma'am!" After they were gone, Andrea turned on the spot; and suddenly had the unpleasant feeling of being forced through a tube much smaller than she was. A moment later she appeared in front of the southern gate.

As soon as she got her bearings, Andrea began inscribing runes on the gate, to strengthen it. Once she was done with that, she went to the top of the wall; and cast, "Amoveo gleba" which she used to make three trenches in a semicircle around the gate. The first trench was a little under a meter deep, and a little over a meter wide. At the bottom she conjured small barbed metal spikes, and filled it with muddy water to obscure them. The second trench was about half a meter behind the first one.

It was nearly two meters deep, and just as wide. Like the previous one, it had barbed spikes at the base. Unlike the previous one however, which had square-dug walls; the innermost wall of the second trench was slopped, and led directly to a parapet made from the displaced soil from the three trenches. The parapets slope was angled so that, despite its height; it would offer those below no cover from the city wall. The parapet ended with a shear drop to the final trench.

The last trench was a two meters wide, and a little more than a meter deep, which when combined with the height of the parapet; meant that the batarians would have to get down a four meter drop. As two finishing touches, she conjured rows of razor-wire, which she attached to the slope of the parapet with a permanent sticking charm; and one meter long barbed spikes at the base of the last trench. Just as Andrea was finishing, she heard the hum of an air-craft overhead.

She looked up and saw a batarian drop-ship heading in to land. Then in her ear, Andrea heard the voice of Corporal Grant say. "Gunny." She immediately put her hand to her ear and responded. "I see it, Corporal. Has Private Kramer linked up with you yet?" "Yes, ma'am. We're setting up now." He replied, to which she said. "Good. Give me a heads up if either of you see movement."


	2. Chapter 2

**AN: WARNING. The following chapter contains adult content including strong language, graphic violence, death and gore. And due to it's content should not be viewed by anyone under the age of 17, 18 or 21 where applicable under law. Reader discretion advised.**

Illyria, Plant Elysium, Vetus System, Petra Nebula.  
June-5-2176  
10:50 PM local time.

The night was calm as Andrea Shepard stood watch with her squad on the city wall. The plant's largest moon was full tonight, and there were only a few small clouds in the sky. The enemy drop-ships which had been screaming through the air only a few minutes ago were gone now. At this moment nothing disturbed the night. It seemed wrong to Andrea that it was so peaceful now, considering what was about to happen.

When she had been in training, Andrea had scoffed at the idea that the wait before a battle was worse than combat itself. Now that she was minutes away from what might very well be the hardest fight of her life, she had no trouble believing it.  
As Andrea was watching the tree line for movement, Private Yamato approached her and asked. "So, Gunny; what do you think our chances are?"

Andrea thought about how to convey her thought process in a way that nether hurt morale, or gave anyone false hope. When she decided how to word it she said. "We're in a strong defensive position, we have both height and cover; and our position cannot be flanked. The proximity of the tree line will make them unable to use their full numbers against us at once. That said, we are vastly outnumbered. Our worst problem though, isn't the enemy's numbers; but rather our own exhaustion."

"We just got done drinking after being up all day, the detectives were about to go home for the night before this happened and the civilians were likely in bed when the call went out. Meaning all of us are fight back the need for sleep. So bottom line, if we can keep ourselves sharp, we should be able to last till reinforcements arrive." The private frowned and asked. "Do you really think the civies will be able to hold up in combat?"

Andrea glanced at the private and seeing how nervous she was; decided that she needed to calm her down. "First off, a good number of those civies are former marines and likely veterans of the first contact war. And secondly, the rest of them are hunters; and shooting an animal isn't so different from shooting a person."

"Except deer generally don't shoot back." Andrea smirked at that and said. "Well, there is that." The private then made a contemplative expression, looking as though she was thinking about something hard and not liking it. Andrea finally asked. "What's on your mind Private?" Yamato looked startled by the question for a moment, before replying. "Permission to speak freely, ma'am?" Andrea studied her for a few seconds be for saying. "Granted."

The Private sighed and asked. "You're going to erase their memories after the battle, aren't you?" From how upset she seemed, Andrea guessed that this was likely the Private's first experience with memory modification. Honesty being the only viable option, she said with a solemn voice. "Yes Private, I will. Let's forget for a moment that I'm about to use battle magic in front of them. You saw Collins's reaction when he saw the outer defenses."

As she said this, Andrea remembered the look of disbelief on the Commissioner's face as he asked how she had dug the trenches, in less than fifteen minutes. And the look of suspicion he gave her, when she said the answer was classified. Andrea shook her head gently and continued.

"We can't allow even the suspicion that some humans have unknown powers reach the Counsel; because they already think the Alliance is hiding something from them. Anything confirming that suspicion is the last thing Humanity needs right now." Upon hearing this Private Yamato sighed again and said. "I know that it needs to be kept secret, but a person's memories are who they are. What right do we have to change that?"

Andrea winced at that, as that was the same argument she had with herself many times. But her own self-doubt was not the issue here, so Andrea told the Private the same thing that she told herself on her better days. "You just said yourself that the secret has to be kept. That being the case, there are only two options available to us. Ether we one, kill everyone who finds out, or b; we modify their memories. Which would you prefer the Alliance ask of us?"

Yamato grimaced at that, but didn't answer. Observing the Private, Andrea realized that she would have to keep a close eye on her after the battle, and more than likely recommend she undergo counseling in her mission report. She knew most Alliance soldiers who knew about magic had the same feelings as the Private. But the fact that she's voicing them; in the middle of a combat op, means she needs someone to talk to about it.

Ether to help her work through it, so she can continue her duties; or to determine if she is able to perform them. The silence was undisturbed for several minutes, until the voice of Corporal Grant came over the wireless, saying. "Movement at the tree line. Eleven o'clock." Everyone on the wall tensed as they turned slightly to the left. A moment later the previous silence was shattered as a veritable horde ran screaming out of the forest.

The first row to emerge from the tree line was easily over a hundred strong, and more rows continued to stream out of the forest seemingly without end. For a fraction of a second the only thing Andrea could think was. _'Bugger.'_ Then she remembered herself and yelled. "Open fire!" Just as she started giving the command, a shot rang out behind them.

As she finished it a batarian in the front row's head disappeared in a red cloud, behind him another enemy's chest exploded; and behind him a third's leg was blown off. As the fifty muggles and one hundred mechs opened up on the approaching enemy's, Andrea pointed her wand at the center of the enemy formation and shouted. "Avada kedavra!"

And continued shooting out the green light of the killing curse, occasionally adding in. "Confringo!" at the edges of their formation, to keep them from spreading out. After all, smaller groups would mean smaller targets. Andrea was surprised by how many of the batarians were falling to her first hits. After all, had they been wearing kinetic barriers, the shields would have stopped the first curse.

The fact that they didn't have shields meant this wasn't the Batarian Military they were fighting, but more likely a ragtag group of pirates and mercenary's. Andrea grinned at the realization, as their odds of surviving the night just went up dramatically. The batarians started to fire back from the open, once they reached the trenches and apparently realized they would offer no cover.

The enemy's charge began to slow as they began stumbling over their comrade's body's; and again as they realized how dangerous the first trench was. Nearly an hour after the fighting had started, the enemy made it to the top of the parapet. The first few to the top immediately jumped down; only to be impaled on the barbed spikes below. After that they took the drop more carefully; which made them much better targets.

Throughout the fighting so far, every time an enemy with a heavy weapon would target the wall with it they were instantly hit by sniper fire. But Corporal Grant was just a second too slow this time, as one finally got off a grenade launcher. As the round streaked in to her left, Andrea turned toward it and shouted. "Protego impes!" Casting a shield in front of her, that would stop almost any physical force or object. But it did nothing to protect those on to other side.

Andrea watched with dread as the round flew toward those in front of her, thirty mechs, fifteen civilians, five law officers; and five of her squad. Private Yamato was standing right in front of her watching the grenade come closer to her group. Just before it hit the Private turned and look at Andrea. Andrea's eyes were wide in horror as she saw the expression's on Yamato's face.

First desperation as she was turning, then shock when she saw the shield; and finally despair when realized what the shield meant. That she, and everyone behind her were about to die. As the round hit, there was a half a second delay before it detonated. Before it blew, Andrea said, in a pain filled voice. "I'm sorry." Those closest to the grenade were killed instantly, as the shockwave ruptured their internal organs; the ones farther away however were not so lucky.

Andrea could not tear her eyes away, as she watched shrapnel rip through Private Yamato's chest and neck, only to be stopped by her shield; trails of blood following the jagged pieces of metal out of her body. Andrea turned as she heard cries of pain behind her. As she finished turning she saw three of her squad mates holding some part of their body that had been shot, to stop the bleeding. The rest were dead or dying.

Andrea could only assume that they been caught out of cover as they watched the grenade detonate. She was now all but alone in the fight. Private Kramer, Corporal Grant and Andrea herself were now the only defense the city had. And with that thought she knew there was only one way left that they could win. Andrea was loathe to use it however, after all it was one of the most dangerous pieces of magic that there was.

A single lapse in control would be all it would take to destroy the very city she was trying to save. But this was an all or nothing fight, and she couldn't afford to hold back. So to that end, Andrea reached up, taped her ear and said. "SSV Agincourt, this is Gunnery Chief Andrea Shepard; requesting to speak to Commander Sanchez. Please respond." After a moment of silence a voice over the wireless said. "This is Commander Sanchez. What's the situation down there Gunny?"

Andrea took a deep breath before replying with. "Sir, the situation is dire. All but five of my squad are dead, three of those are unable to fight. All of the civilians aiding the defense are dead as well. Our line is about to collapse. Requesting authorization to use a class two MWMD." The wireless went silent for what felt like an eternity. Finally, Commander Sanchez said. "Authorization granted Gunnery Chief."

Andrea calmly stood from her cover and look to the other side of the wall. She saw that the batarians weren't even firing anymore, thinking that they were all dead. Seeing this, Andrea summoned all of her grief and rage until the two emotions were all that she was; then pointed her wand at the batarians and cried out. "Ferus Incendium!" A torrent of fire shot out of her wand and quickly engulfed everything she could see.

Andrea could feel the flames as though they were a part of her; as they grew she felt them form into dragons, griffins, chimeras and virtually every other monster known to wizard kind. She felt as hundreds, and then thousands of beings were burned and turned to ash. She felt the flesh melt off their bones, heard their pitiful cries of fear and agony. In that moment Andrea felt like the most powerful being in the galaxy, anything that opposed her would burn in the flames of her wrath.

After a few minutes of this, the last of the batarians were dead. She then began burning the forest; reveling in the destruction. She continued until she thought. _'This is wrong, why am I doing this?'_ The immediate response in her mind was. _'What good are those trees doing anyone? Besides, how could something that feels this good possibly be wrong?'_ That didn't sound like her at all. Andrea frowned as she realized how much she was being influenced by this spell.

She tried to stop, but the flames didn't want to go out; and she had to battle her own magical core to cut off the spells power. Finally, she managed to end the spell. When she looked up, she was horrified by what she saw. Everything within eight kilometers of the wall had been reduced to ash. This was why, even in the Alliance, who usually had no problem with the dark arts; Fiendfyre was a measurer of last resort. Even those with the strongest of wills had trouble controlling the spell.

Andrea shakily reached up to her ear and said. "SSV Agincourt, this is Gunnery Chief Shepard. Reporting all enemy's neutralized, the city is intact. No human collateral damage . . . the forest is a lot smaller though." The line was silent for a moment, then. "Acknowledged Gunnery Chief. Continue to hold your position until you are relived." To which Andrea replied. "Understood Agincourt, Shepard out."


End file.
